A leading executive of South Korea's troubled Hyundai conglomerate committed suicide last night, throwing himself from the 12th floor of the company's headquarters in Seoul.

Chung Mong Hun, 55, had been under investigation for making illegal payments to the government of North Korea and had been indicted on charges of false accounting in an attempt to cover them up.

He became chief executive three years ago, feuding bitterly with his brother Chung Mong Koo after their father Chung Ju Yung, who founded the company as an auto repair shop in 1940, stepped down. He broke with Korean tradition by naming the younger son, Chung Mong Hun, head of the corporation three years ago, causing a rift between the brothers.

As part of a restructuring plan to solve the business's financial problems, Chung Mong Koo took control of the Hyundai motor corporation.

Chung Mong Hun, described by one profile writer as an "unsocial man" who worked long hours, was head of Hyundai Asan, which had interests in tourism and was promoting joint ventures with North Korea. In January he was banned from leaving the country pending an investigation into allegations of illegal payments of hundreds of millions of dollars to officials in North Korea to ensure a summit between the two countries took place in 2000. South Korean police announced two weeks ago they were stepping up their investigation into the affair, in which company money was laundered by a suspected go-between to guarantee the historic meeting went ahead.